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E. THOMSON.

ELECTRIC LAMP.

No. 256,605. Patented Apr. 18,1882.

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ELECTRIC LAMP. No. 256.605. Patented Apr. 18, 1882.

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UNITED STATES PATENT OFFICE. i

ELIHU THOMSON, OF NEW BRITAIN, CONNECTICUT, ASSIGNOE TO TIIE AMERICAN ELECTRIC COMPANY, OF SAME PLACE.

ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 256,605, dated April 18, 1852,

Application filed June 20, 1881. (No model.)

Toxlll whom it may concern:

Be it known that I, ELIHU THOMSON, a citizen of the United States, residing in New Britain, county of Hartford, State of Connecticut, have invented certain new and useful Improvements in Electric Lamps, ot' which the following is a full specilication.

My invention relates to electric lamps ofthe arc type, and has for its object the feeding' of a carbon pencil unprovided with any supporting-rod by mechanism that shall secure great uniformity of consumption of said carr bon pencil, steadiness of light, duration oflight,

compactness ofthe lamp mechanism, and other advantages.

My present invention, so far as concerns the devices for ft eding the carbon pencil, is based upon the employment of two catches or clamps operating in somewhat the same way as those described in Letters Patent No. 220,287, October7,1879, Houston andThomson,whereintwo spring clips or catches operate upon the lower carbon, and are combined with stops set to limit the movement of the catches at different points in the movement of their actuating devices. My present invention ditfers from that described in the above patent in that devices are combined with the two clamps and their operating'electro-magnet,whereby the strength of said magnet is intermittentlyvaried in obedience to the changes in resistance at the arc. In my present invention, also, the two clamps act upon an upper carbon, and are combined with devices whereby they may be disengaged from the carbon and release it, so as to allow it to come into contact with the lower carbon. My present invention is also diterentin other respects. Theditterenceswillbeapparcntfrom .the accompanying` drawings and specification,

and will be specified in the claims. I also employ a shunt-magnet or derived circuit around the arc for governing a shunt-contact or short circuit around a second magnet for operating the feed. y

Myinvention further relates toim provements in the construction and arrangement of parts to control the access of the current to the lamp and enhance its convenience and symmetry.

Figure l is a front view of a lamp embodying my invention; Fig. 2, the saine with thc paits exposed to view and portions in section for ease of description, Fig. 3, the arrangement of catches or clamps for effecting a feed ofthe cai-bon pencil; Fig. 4, the shunt-magnet and its short-circniting contacts and armature. Fig. 5 shows the means of suspending the lamp when ont of use, Figs. Gand 7, a simple switch attachmentfor short-circniting the lamp when it is placed in the position shown in Fig. 5; Fig. 8, a modification adapting the lamp to bc raised and lowered.

I will nowprocced to describe my invention by reference to the figures.

In Fig. 1, B is the casingeontaining theregulating mechanism;l3, a tubular extension for accommodating the length ot' the carbon pencil E. T is a cap or covering for the latter. This cap is removed when the pencil is inserted into the lamp, as hereinafter more fully specified. Plates ot' ironor other metal, P P P P', complete the casing of the lampbex. Thin metal blades, preferably three in number, at one hundred and twenty degrees apart, R Pt It, pass downward inside the lamp-globe for the support ofthe lower-carbon holder, h, the edges ofthe blades It It It being turned toward the carbons or light focus E E to avoid shadow. Small catches q q are turned outward under the edge of the globe, and aii'ord a tirm support for it, but are arranged so as to be readily rotated so as to free the globe, or removed from under the edge of the globe in any weil-known manner. A small bent lever, Z, and screw 7c clamp the holder It, which is made in two parts, the portion to which the lever lis carried being movable, as usual in the art. Supports II Hf, hinged to the lainp-body, are arranged to be fastened to any suitable surface for suspending the lamp. Connecting wires tteXible in character unite the two portions of 9o loidal pole is traversed by the current and attracts its armature L,pivoted at O, the open ing in the armature corresponding to the pole of the magnet M. This form of magnet is'described in a piior application for Letters Patent, and is the foi-in I prefer to employ, although a simple electro magnet and armature or axial coil and core inay be used, when suitably arranged, to take iis place, The armature-lever L, which maybe provided with a dasli-pot or othi r check motion to prevent sudden changes of position, serves to 1aise and lower a clamp, C, provided with a movable or pivoted clamping-toe, t,or catch, and by which the carbon rod ll is gripped and moved downward. A spring, S, holds the toe or catch t in place, except when the clamp G and armature L are lowered so far as to bring thc piolonged end of the toe t in contact with the stop e. When the prolonged end ofthe toe t strikes the stop e the'clamp O is loosened and free of the carbon rod E. A second clutch or clamp, G, suitably guided, as through a ccntral opening iii the plate IJ P', and likewise provided with a toe, t,stop d, and spring S,occu pies a position as shown, and forms the lower guide for the carbon pencil E. 'Ihe clutch G is also elevated and depressed by the armature L acting on a second lever, L', pivoted at f, to which it is linked, and the toetis opened by the stop d. When the arinature-lever L and lever L are down the spring S closes the toe tot' the clamp G, when the armature is raised by the attraction of the magnet M.

Any other clamping devices, many ot' which are now known and used in the art, may be substituted for those shown, provided they admit of thc action as above described.

As the parts aie arranged the clamp C moves for a given movement of the armature L through about twice the space that the clam p G is at the same time moved, and as the two clamps act to pull the carbon pencil E downward the eii'ect is that for every upward and downward movement of the arm atnre L a portion ofthepencil E is carried downward through the clamps toward the lower carbon, E', and the carbon pencil E is free to drop only when the two stops c and d have acted to open the toes t and t ofthe respective clamps C and G. In the latter case, which takes place when the current lin the magnet M fails for a sufficient interval of time, and allows the armature L to be sufficiently lowered, the carbon rod E falls freely. rIhis occurs at the stoppage of the lamp-current itself, or of the current in the magnet M alone for a suitable interval. The carbons are therefore always free to fall into contact before the current traverses the lamp.

It is obvious that the clamp G might be. connected withitsoperatingdevices atsuch apoint that its movement would be greater or less than twice the movement of G. It is also to be understood that other devices might be einployed for imparting different rates of movement to the clamps under the same movement ot the devices operated by the electro-magnet.

An electro-magnet, K,is provided, traversed by a derived currentcircuit around the arc, and

the variations of its power, acting on a movable armature, A, serve to close electric contacts, which form a shunt or short circuit around the lifting-magnet M, while the spring Z opposes the movement of the armature A toward the magnet K. Reference is had to Figs. 3 and I for more detailed views of the parts, which will be hereinafter described.

The circuitconnections are as follows: The current enters on the side of the lamp atH a, and passes from thence to the coils of the magnet M, with a branch to one of the eoutacts,p, Fig. 4, controlled by the shunt-magnet K. rIhe other end ofthe inagnet-coil h'I is carried to its core, and from there the current passes to the upper metal work ofthe lamp to which said corc is attached, and finds its way through various connections and metallic contacts among the moving parts to the two clamps G and G, from which it passes to the carbon pencil E through the surfaces in contact. \Vhen these are iii sufficient, as with a very heavy current, contactsprings are placed at any convenient points, bearing against the carbon pencil in a well-known inaniiei. The current passes the arc from E to E and up through one of thc blades It It It, which are suitably insulated to prevent electrical connection between the supports of the upper carbon and those ot' the lower, except through the cii'cuitpaths, as described herein. 'Ihe current passes up the blade It to a vertical rod. o', suitably iii sulated from the supports otthe upper :an bon and out at uy II'. Insulation is provided at all points where necessary in a manner well understood iu the art and indicated in black, Fig. 2. rIhe connections of the magnet K are any convenient contacts ot' the two extremities of its coils with the upper' and lower cai-bons, respectively. In the tigui'e, one

contact is made to the rod 0' in metallic connectioii with the lower carbon, as shown, and the other to the magnet-core of I( itself, which is in metallic connection with the upper can bon.

rIhe operation of the lamp as thus consti tiited is as follows: By Ithe removal of the cap 'E the long carbon E is inserted into the clamps C and G, while the carbon E' isinserted below the bottoni plate bearing the holder h, and which plate has the usual opening for the purpose. The lengths are such that the contact at E E' will be quite near the clamp G at the start. Ihe globe of thc lamp may or may not be in place when the earbons are inserted. When the current is sent through the lamp the magnet M attracts its armature L, raising the latter, which in turn lifts the clamps C and G; butG is only lifted a portion of the distance that C is lifted, this difference of range being due tothe connections of parts, as shown in Figs. 2 and 3, and will be understood by any skilled ineehanieian.

Ihe relation of the clamps to the carbon rod will be readily understood from an inspection of Fig. 3. The clamping-toes of both clutches bear upon the. rod in such a way that an tit- IOO IOS

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tempt to draw the carbon rod upward through either of them would cause the toes to bind against the side ot' the rod and thus prevent the rodi'rom slipping through theclutch. Conversely a movement down ward ofthe support or clamp for either clutching-toe would cause said toe to engage with or lock positively against the side ot' the rod, so that the rod would be compelled to move with the toe. The springs which act upon the toes hold them in sutlicient frictional contact with the rod to allow either clamp and clutching-toc to lift the rod 5 but as will be readily understood therod cannot move any faster than the more slowly movingot1 the two clutches, owing tothelockiugactionwhich occurs upon an attempt to move the carbon rod bodily upward through the clutch. Then the armature L rises both toes t and t, being freed ot' their stops c and d, i'all into place lagainst the carbon pencil E, being assisted by the springs S S'. A further movementot' the clamp G upward allows a separation of the carbons at E E' and the formation of an arc. The movement, however, is only that of the lower clamp, since the lower clamp does not allow the carbon to slip upward through it, and therefore the upper clamp moves upon the carbon instead ot' carrying the carbon with it, as it would otherwise do, and assumes a position in readiness for propelling the. carbon downward. When the arc has slightly7 increased in length from combustion ofthe carbons, the shunt-magnet K becoming active, the armature A is attracted, shunts the current from the magnet M, and the latterlosing its magnetism, the armature L descends, lowering the clamps C and G at the same time; but the clamp G moves through more space than G. Hence the carbon pencil is pushed down through the clamp G an amount equal to the difference ot' their ranges. This feeding action is rendered certain by the arrangement of the toes t' tot the clamps, which admit motion of the pencil downward only. 'l`husat every movement of the armature L a ieed of the carbon E is eifected.

When the carbon E is so far consumed that its upper end reachesthe clamp C the feeding, as above described, ceases, but is supplanted by asuccession of drops and lifts ofthe carbon by the clamp G acting alone. The change in the manner ot' feedingis noticeable in the light evolved, and serves as an indication that the carbons need replacing. In this latter case a new carbon, E, is introduced and the piece of upper carbon unconsumed utilized as a lower carbon, E'. By this plan the waste of stub ends of carbon is greatly reduced. The stub end which is thus utilized for a lower carbon may be electroplated with copper, or otherwise coated to increase its durability.

Fig. 3 shows the relation of the clamps C and G more fully, where similar letters are used to indicate the same parts as in Fig. 2. The action ofthe parts has been before described, but the form of the toes t' t is here shown; audit will beI evident to a skilled mechanic that, as shown, a downward movement of the carbon -pencil will be much more easily effected through the clamps than an upward movement. It results from this that any difference ot" range in the movements of the two clamps C and G is accompanied by a downward feed of the pencil E. Y

Fig. 4 shows thearrangementot'the magnet K and its accompanying parts. The magnet pole is sloped, and an armature, A, as a piece of bar-iron suspended upon alever,L",pivotcd at V, land when attracted makes contact atp q in opposition to the spring Z. The contacts p g are respectively connected to the extremities ofthe magnet-coil M, so that when in contact but little currentpasses through the coils M, it being shunted by the contacts. A very small increase ot arc-resistance will, with the parts as described, effect a closingot' the contacts and consequent feed ofthe carbon pencil E, as before described. A suitable stop, Z', prevents the armature A from moving, except through quite small range.

The use of the swinging hinge-joints m m., Fig. 1, may now be described.

Fig. 5 shows the lamp in position when the carbon E is being inserted, the lamp turnedinto a horizontal position, and the cap T ott'the end ofthe tubular extension B'. rlhe cap T is pret'- erably hinged to B', as shown. Ahookma, may be provided to secure and retain the nearly horizontal position, aproper projection from the lamp-case B being likewise provided for engagement ot'said hook x. When the carbon Eis inserted, asjust described, it is essential that no4 current be allowed to pass through the circuit, orthatthe lalnp should be switched out of circuit. Thiseil'ectbyattachingacontact-spring, U, Figs. 6 and 7, to the joint H' in metallic connection with the exit-point ofthe current from the lamp, and providing a contact-surfaced, in connection with the entrance-point of the current to the lamp. Vhen the lamp is hung vertically the surface P3 is out ot' contact with U, as in solid lines, Figs. 6 and 7; but when thrown out of this position the spring U and surface P3 contact with each other and allow the current to pass without entering the carbons ot the lamp. Any equivalent short-circuiting device may be used whose opening and closing are dependent on the position of the lamp. Vhen, however, the lamp is hung at an inconvenient height it may be lowered for attention to its carbons, and afterward raised into position. This is accomplished, as in Fig. 8, by replacing the pieces H H', Fig. 1, by copperwire ropes running over metallic pulleys l P2, connected to the circuit in which thelamp is placed and insulated from each other. A yoke, Y', of metal, has the ends of these wire ropes H H' not attached to the lamp fastened to its ends, but insulated from said yoke Y', as shown in black in the ligure. Acord or rope, R3, is attached to the center of said yoke, by which its position may be controlled and the IOO IIS

lamp raised and lowered. Then fully lowered the yoke Y comes into contact with the pulleys or their' supports and connects them metallically, thus shunting the current around the lamp.

I claiml. The combination, with the upper carbon electrode in an electric lamp, ot' two differentially-moving clamps, each arranged so that its clamping edges orjaws tend to propel the carbon downward orto prevent movement of the carbon upward through the clamp, and means for disengaging said clamps to allow the carbons to come together upon an abnormal increase in the length of arc.

2. The combination, substantially as described, with an armaturelever, ot' two lifting-l clamps connected thereto at dillerent distances from its fnlcum, so that said clamps may have a different range of movement. with a given movement of the armature. 3. The combination, substantiallyv as described, wit-h a carbon electrode, of two difterentiallymoving clamps and an operatingarmature provided with supporting-links or similar rigid supporting devices l'or both clamps.

4. The combination, Vsubstantially as de scribed, with the upper carbon in an electric lamp, of diii'erentially -moving clamps ar ranged, as described, to move at ditt'erent speeds, and each consisting of a movable body and pivoted clamping-toe, said clamping-toes being arranged with relation to the carbon, as described, to lock against the carbon, so as to prevent a movement upward ot' the carbon through a clamp or to move the carbon downward positively with aclamp.

5. rlhe combination, substantially as de scribed, with a carbon rod, ot'two diii'erentiallymoving clamp-bodies, clamping-toes arranged as described, so that a shitting downward ot' the clamp with relation to the carbon rod is prevented by the locking ot' the toe upon the rod, springs for holding the clamping-toes in engagement with the carbon, and steps arranged to release said clam ping-toes.

6. In an electriclamp, clamps C and G, movable toes t t, springs S S', and stops c and d, in combination with a movable armature orits equivalent, and means for giving a differential movement to the clamps, whereby the following actions upon a carbon pencil are et' fected, viz: a free release ot' said carbon pencil when said armature is unacted upon by its controlling-magnet, a litt ot' said pencil from cont-act with the other carbon pencil when said armature is actedupon by its controlling-inagnct, and a downward i'eed due to a difference ot' range ot' said clamps when said armature is again released from said magnet.

7. The combination, substantially as described, with two lifting or propelling clamps having a diilerent range ot' movement, ot a propelling` electro-nntgnet for said clamps, a derived-circuit electro-magnet, and a circuit closer and breaker for intermittently controlling the tlow ot' a current through the propelling electromagnetin obedience to the changes ot' arc-resistance.

S. The combination, substantially as described, with the plate P, supporting thelamp mechanism and its inclosing-caseB, ot'the depending ribs R R it, placed with their edges to the light, clamping` devices i'or the lower carbon carried by said ribs, supports g (l, and the globe carried by said supports and surrounding the ribs and the light-giving t'ocus.

9. ln an electric lamp, a hanging support consisting ot' the parts il Ll', substantiallyT such asdescribed, and movable Ijoints m n1, whereby a rapid change otl the position ot' said lamp is ei't'ected, in combination with a lamp-body,], and extension B', and removable cap thereto, T, whereby a renewal ot' carbons may be rapidly and conveniently effected, as described.

l0. The combination, substantially as dcscribed, of an electric lamp hung on pivoted supports, and a shunt-circuit closer for completing apath around the lamp when the lamp is changed from its vertical position.

ll. ithe combination, substantially as described, ot' the rigid supporting-arms, the hinged hangingarnis,and ashuntcircnitcloser, all combined in the manner set lorth, so that when the lamp is swung i'rom the vertical said lamp is cut out ot' circuit.

l2. rihe combination, substantially as described, of the main l'rame ot' the lamp, the jointed supports l H, casing and tubular extension AB B', removable cap T, and automatic cut-outforcompleting a circuitaround the lamp when the latter is swung into a horizontal position t'or thepurposeofinsertinga new carbon.

ELHU THOMSON.

Witnesses:

W. B. TnoMsoN,

VILBUR Rien.

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